1. Solving One-Step Equations
COURSE 3 LESSON 2-1
Solve –3 = m – 16.
Since 16 is subtracted from m, you must add 16 to each side to isolate m.
–3 = m – 16
– = m – Add 16 to each side.
13 = m Simplify.
–3 = –3 Subtract.
– – 16 Substitute 13 for m.
Check –3 = m – 16 Check the solution in the original equation.
2-1

2. Solving One-Step Equations
COURSE 3 LESSON 2-1
After Vida adds 17 new shells to her collection, she then has a total of 52 shells. Write and solve an equation to find how many shells she had before adding the new ones.
Equation s + 17 = 52
Words original number of shells plus new shells = total
Let s = the original number of shells.
Since 17 is added to s, you must subtract 17 from each side to isolate s.
s + 17 = 52
2-1

3. Solving One-Step Equations
COURSE 3 LESSON 2-1
(continued)
s + 17 – 17 = 52 – 17 Subtract 17 from each side.
s = 35 Simplify.
Vida had 35 shells before adding the new ones.
Check s + 17 = 52
Check the solution in the original equation.
Substitute 35 for s.
52 = Add.
2-1